Commonly rollers used in support structures have a roller body with a peripheral formed rim adapted in use to engage a linear guide track to roll there along. The rollers commonly include an axially extending shaft with suitable bearing means to allow the roller body to freely rotate about a rotation axis defined by the shaft with the shaft having short axially extending stub shaft parts extending outwardly of side walls of the roller body. The short stub shaft parts are adapted to engage and be retained in a downwardly open retainer recess in side walls of a housing part of some form, the minimum dimension of the recess being slightly less than that of the stub shaft parts such that the stub shaft parts will, when being assembled snap fit into the retainer recess and be held thereby.
Typically, the shafts including the extending stub shaft parts will be a suitable metal and the housing part may be made from molded plastics material. Such a configuration is shown, for example, in the specification of Australian Patent No. 779340. In this specification the roller support assembly comprises an outer housing part adapted to be secured in a downwardly facing recess of a door, window or similar sliding panel. The outer housing part includes an inner support carriage carried by the outer housing part and adjustable in height relative to the outer housing part. The inner support carriage itself carries a bogie member in releasable manner that carries one or more rollers fitted between side walls of the bogie member in a manner as described in the foregoing.
While such assemblies have worked satisfactorily, the downwardly open retainer recesses in the side walls of the bogie member provide a degree of weakness and therefore greater flexibility for the side walls that are made from molded plastics material, which can cause difficulties and lower service life when under reasonably heavy loads. A further practical difficulty is that in roller support assemblies as described, the peripheral formed rim of the roller (or rollers) extends below the lower edge of the door or other panel in which it has been installed. There is then a risk that the door or other panel will, during installation and before the roller is correctly engaged with the linear guide track on which it is intended to roll, will be supported on the roller peripheral rim and possibly dragged across surfaces transverse to the peripheral rim. Given that the roller body and the formed peripheral rim are commonly also made from molded plastics material, such actions during installation have a significant risk of causing damage to the peripheral rim of the roller.